How to separate my array into some parts in discord.js?-CodePudding

I'm doing pagination in an embed and I wanted to split 4 elements from an array for each page. How do I do this? (to update when I click the button). Until then I have only the first step which is to get the first 4 elements, from the first page, with:

.slice(0, 4)

How do I get the next 4, and the next, and so on...

CodePudding user response：

you need to define:

currentPage variable (set to 1 as default value)
pageSize - how many items should be for one page
countPages - for calculation, rounded in bigger side

I have written 3 methods

loadFirstPage()
loadNextPage()
loadPrevPage()

const input = [1,2,3,4,5,6,7,8,9,10,11,12,13];
let currentPage = 1;
let pageSize = 4;
const countPages = Math.ceil(input.length / pageSize);


function loadFirstPage() {
    currentPage = 1;
    return [...input].splice(0, pageSize)
}

function loadNextPage() {
    const nextPage = currentPage   1;
    if (nextPage <= countPages) {
        currentPage = nextPage;
        const startIndex = currentPage * pageSize - pageSize;
        return [...input].splice(startIndex, pageSize)
    } else {
        currentPage = countPages;
        const startIndex = currentPage * pageSize - pageSize;
        return [...input].splice(startIndex, pageSize)
    }
}

function loadPrevPage() {
    const prevPage = currentPage - 1;
    if (prevPage >= 1) {
        currentPage = prevPage;
        const startIndex = currentPage * pageSize - pageSize;
        return [...input].splice(startIndex, pageSize)
    } else {
        currentPage = 1;
        const startIndex = currentPage * pageSize - pageSize;
        return [...input].splice(startIndex, pageSize)
    }
}

console.log('output data: ', loadFirstPage(), 'current page: ', currentPage);

console.log('output data: ', loadNextPage(), 'current page: ', currentPage);
console.log('output data: ', loadNextPage(), 'current page: ', currentPage);
console.log('output data: ', loadNextPage(), 'current page: ', currentPage);
console.log('output data: ', loadNextPage(), 'current page: ', currentPage);

console.log('output data: ', loadPrevPage(), 'current page: ', currentPage);
console.log('output data: ', loadPrevPage(), 'current page: ', currentPage);
console.log('output data: ', loadPrevPage(), 'current page: ', currentPage);
console.log('output data: ', loadPrevPage(), 'current page: ', currentPage);